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/* ISC license. */
#include <unistd.h>
#include <errno.h>
#include <signal.h>
#include <skalibs/allreadwrite.h>
#include <skalibs/sgetopt.h>
#include <skalibs/strerr2.h>
#include <skalibs/types.h>
#include <skalibs/tai.h>
#include <skalibs/iopause.h>
#include <skalibs/djbunix.h>
#include <s6/config.h>
#define USAGE "s6-setlock [ -r | -w ] [ -n | -N | -t timeout ] lockfile prog..."
#define dieusage() strerr_dieusage(100, USAGE)
typedef int lockfunc_t (int) ;
typedef lockfunc_t *lockfunc_t_ref ;
static lockfunc_t_ref f[2][2] = { { &lock_sh, &lock_shnb }, { &lock_ex, &lock_exnb } } ;
int main (int argc, char const *const *argv, char const *const *envp)
{
unsigned int nb = 0, ex = 1 ;
unsigned int timeout = 0 ;
PROG = "s6-setlock" ;
for (;;)
{
int opt = subgetopt(argc, argv, "nNrwt:") ;
if (opt == -1) break ;
switch (opt)
{
case 'n' : nb = 1 ; break ;
case 'N' : nb = 0 ; break ;
case 'r' : ex = 0 ; break ;
case 'w' : ex = 1 ; break ;
case 't' : if (!uint0_scan(subgetopt_here.arg, &timeout)) dieusage() ;
nb = 2 ; break ;
default : dieusage() ;
}
}
argc -= subgetopt_here.ind ; argv += subgetopt_here.ind ;
if (argc < 2) dieusage() ;
if (nb < 2)
{
int fd = open_create(argv[0]) ;
if (fd == -1) strerr_diefu2sys(111, "open_create ", argv[0]) ;
if ((*f[ex][nb])(fd) == -1) strerr_diefu2sys(1, "lock ", argv[0]) ;
}
else
{
char const *cargv[3] = { "s6lockd-helper", argv[0], 0 } ;
char const *cenvp[2] = { ex ? "S6LOCK_EX=1" : 0, 0 } ;
iopause_fd x = { .events = IOPAUSE_READ } ;
tain_t deadline ;
int p[2] ;
pid_t pid ;
char c ;
tain_now_g() ;
tain_from_millisecs(&deadline, timeout) ;
tain_add_g(&deadline, &deadline) ;
pid = child_spawn(S6_LIBEXECPREFIX "s6lockd-helper", cargv, cenvp, p, 2) ;
if (!pid) strerr_diefu2sys(111, "spawn ", S6_LIBEXECPREFIX "s6lockd-helper") ;
x.fd = p[0] ;
for (;;)
{
ssize_t rr ;
int r = iopause_g(&x, 1, &deadline) ;
if (r < 0) strerr_diefu1sys(111, "iopause") ;
if (!r)
{
kill(pid, SIGTERM) ;
errno = ETIMEDOUT ;
strerr_diefu1sys(1, "acquire lock") ;
}
rr = sanitize_read(fd_read(p[0], &c, 1)) ;
if (rr < 0) strerr_diefu1sys(111, "read ack from helper") ;
if (rr) break ;
}
if (c != '!') strerr_dief1x(111, "helper sent garbage ack") ;
fd_close(p[0]) ;
if (uncoe(p[1]) < 0) strerr_diefu1sys(111, "uncoe fd to helper") ;
}
pathexec_run(argv[1], argv+1, envp) ;
strerr_dieexec(111, argv[1]) ;
}
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